Coloring of hair with a permanent or long wearing dye generally involves the oxidative reaction of a phenylenediamine, typically in the presence of a hydroxybenzene derivative to produce the indo-dye. An aryldiamine is normally mixed with a solution consisting of an oxidizing agent, usually hydrogen peroxide, and another agent such as a resorcinol. This mixture is then applied to the hair for a period of time long enough to impart a color which is resistant to shampooing and being rubbed off. With such a permanent dyeing system the color is formed within the hair fiber and is therefore trapped and not able to diffuse out. Permanent hair coloring procedures are usually performed at an alkaline pH between pH 8.5 and 11, which can cause some damage to the hair. Such oxidative dyeing of hair is generally accompanied by the readily perceptible deterioration of tactile properties of hair manifesting themselves in a raspy feel and increased difficulty in combing.
The alkaline conditions under which the treatment procedure must be carried out further damages the hair and effects the morphological changes in the cuticular surface of the hair fibers as described by Mahrle, et al., "The Use of SEM to Assess Damage to Hair" in Hair Research; edited by C. E. Orfauos, W. Montagna and G. Stittgen; (Springer-Verlag; New York, 1981).
Although practically speaking most, if not all, permanent hair coloring procedures are performed with alkaline media, neutral to acidic permanent hair coloring processes have been taught. For example, Shesiedo (JP 53130443) teaches that the combination of a trihydroxybenzene with a metal salt of Cu(II), Fe(II) or Mn(II) in contact with hair over 60 minutes at pH 7 will impart a dark color to the hair . Very gradual hair coloring at pH less than 6 is taught in JP 85039645 (Bristol-Myers) by using a trihydroxybenzene or a trihydroxytoluene and a phenylenediamine in combination with air as the oxidant. Brown shades are achieved after repeated applications of the mixture.
It is nonetheless apparent from the prior art that alkaline solutions of oxidizing materials are required in order to permanently dye hair in a relatively short period of time to achieve colors other than black or brown.
Typical of various prior art references related to the field of this invention are the following:
U.S. Pat. No. 4,620,850 (Bachmann et al.) discloses a composition for dying hair comprising derivatives of indole. The composition further comprises compounds such as protocatechualdehyde. The dyeing takes place at pH 2 to 4;
U.S. Pat. No. 3,871,818 (Kinney et al.) which discloses a solution containing an alkyl dialdehyde compound in combination with at least one nitrogen containing compound for changing the color of keratinous materials, particularly human nails;
U.S. Pat. No. 4,695,285 (Chung-Bong-Chan et al.) which discloses the use of azidoindole for dyeing hair. The composition may also comprise a color coupler for interacting with azidoindole;
U.S. Pat. No. 4,453,941 (Jacobs) which discloses a hair dye composition comprising indole derivatives in admixture with certain compounds having a reactive nitrogen moiety;
U.S. Pat. No. 4,391,603 (Rosenbaum et al.) which discloses the use of hydroxyl derivatives of benzaldehyde for coloring keratin fibers without an oxidizing agent.
None of the foregoing references nor any other prior art teaching of which the applicant is aware discloses the use of the method and compositions disclosed in the present application.